Hunter Fan PH20-30A - Manual (Page 14)




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The Falconaire PH20-30A is a Microprocessor Based Direct Spark
Ignition, thermostatically controlled heater. The control utilizes a microprocessor
to continually and safely monitor, analyze and control the proper operation of the
gas burner. Value added features such as combustion blower control, LED
diagnostic output, automatic one hour reset, and multiple ignition tries highlight
the controls benefits
.
OPERATION
POWER UP/STANDBY
When the main power switch is turned on, the control will reset, perform a
self check routine, initiate full time flame sensing, and enter the thermostat scan
state
.
HEAT MODE
When a call for heat is received from the thermostat, the control will check
the combustion pressure switch for normally open contacts. The blower is then
energized and once the combustion pressure switch contacts close, a 3-second
prepurge delay begins. Following the prepurge period, the gas valve is
energized and sparks commence for the trial for ignition (TFI) period.
When flame is detected during TFI, sparks are shutoff immediately and
the gas valve and combustion blower remains energized. The thermostat,
combustion pressure switch, and main burner flame are constantly monitored to
assure the system continues to operate properly. When the thermostat is
satisfied and the demand for heat ends, the main valve is de-energized
immediately, the control senses the loss of flame signal and initiates a 60-second
postpurge period before de-energizing the combustion blower.
FAILURE TO LIGHT - LOCKOUT
Should the main burner fail to light, or flame is not detected during the first
TFI period, the gas valve is de-energized and the control goes through an
interpurge delay before another ignition attempt. The control will attempt two
additional ignition sequences before going into lockout. The valve relay will be
de-energized immediately, and the combustion blower will be turned off following
the post purge period.
Recovery from lockout requires a manual reset by resetting the thermostat,
turning off the main power switch or removing 12-volt power for a period of 5
seconds.
If the thermostat is still calling for heat after one hour the control will automatically
reset and attempt to ignite the burner again.